The use of walking aids such as walking sticks, elbow crutches or axilla (underarm) crutches by users with short or long term leg injury is commonplace. As the tip of the walking aid is placed on a ground surface during walking a large load is transmitted to the upper body (at the hands, wrists, arms, shoulder, back, neck or joints such as elbow joints or shoulder joints), which can result in upper body pain and/or fatigue which in turn may lead to crutch palsy, aneurysms, thrombosis or other serious conditions.
In an effort to damp the impact force resulting from the load transmitted to the user during walking, walking aids incorporating shock absorbers have been developed. These known shock absorbing crutches include dedicated spring-loaded crutches where the shock absorber is permanently integrated into the crutch body and which requires the user to purchase and use the spring-loaded crutch in preference to the traditional rigid crutch.
The disadvantages associated with the use of dedicated shock absorbing crutches include the extra expense of purchasing the new crutch, the increased weight of the crutch which can affect manoeuvrability and the inconvenience of using a shock absorbing crutch on ground surfaces which do not require shock absorption and which can lead to instability for the user.
More recently, conversion kits have been developed to fit to existing crutches.
U.S. Pat. No. 7,395,829 titled “Shock Absorber Crutch and Shock Absorber Kit” discloses a spring loaded shock absorber which clamps onto the lower end of the body of the crutch.
U.S. Pat. No. 6,055,998 titled “Shock Absorbing Fixture” discloses a spring loaded shock absorber which is removably fitted into the lower end of the body of the crutch.
US2005/0129456 titled “Crutch Apparatus and Method” discloses the use of a gel shock insert (rather than a spring) located between a fixed tube stop and a plug located in a slide tube slidingly engaged with the fixed tube.
However, the shock absorbers disclosed in the documents outlined above suffer from one or more of the following disadvantages:                Attachment of the shock absorber to the body of the crutch can require the use of tools and therefore be inconvenient to convert between a shock absorbing crutch and a rigid crutch;        Multiple individual parts can make fitment of the crutch with the shock absorber inconvenient;        Attachment of the shock absorber to the body of the crutch can affect the integrity of the body of the crutch and therefore present a danger of failure of the crutch during use; and        The lack of adjustability of the shock absorber can make use of the shock absorbing crutch limited over different surfaces or with users of different weight.        
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinence of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein; this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in Australia or in any other country.
It is acknowledged that the term ‘comprising’ may, under varying jurisdictions, be attributed with either, an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprising’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.